The present invention relates to an electronic image-pickup type endoscope which comprises an image-pickup unit including an objective optical system, a solid-state image-pickup device, and electronic components associated therewith.
Multifunctional electronic endoscopes have recently been developed. In a conventional electronic endoscope, an optical image is picked up using a solid-state image-pickup device, such as a CCD (Charge-Coupled Device), and observed on a monitor. This type of endoscope includes an image-pickup unit having a solid-state image-pickup device and electronic components associated therewith. The unit is accommodated in a sealed case. The case is arranged inside the endoscope.
Endoscopes are normally sterilized with a gas such as ethylene oxide gas. During sterilization, the endoscope is maintained in a reduced-pressure environment. In order to prevent the outer case of the endoscope from exploding, the interior of the endoscope is also evacuated. However, since the case accommodating the image-pickup unit is sealed, a pressure difference occurs between the case interior and the endoscope interior upon evacuation of the latter. When gas sterilization is repeatedly performed, a decrease in strength at the adhered portions of the image-pickup device and the case, and hence peeling thereof, tend to occur. In addition, when a portion is shielded with a conductive adhesive, this results in incomplete conduction, thus degrading the shielding effect.
The above problems are also encountered when endoscopes are transported by air. When an aircraft reaches high altitude, the ambient and internal pressures of endoscopes are reduced, thereby causing the above phenomenon.